The present invention relates to the induction of forces by injection of fluids through a conduit having a unique internal geometry. More particularly, it relates to an apparatus and method of fluid injection aimed at producing and employing aerodynamically induced forces.
Injection of fluids, liquids, and in particular gases, through one conduit or a plurality of conduits, is a common mean to produce an aerodynamically induced forces acting on objects. Without derogating generality, the present invention relates commonly to the injection of air, although in general the present invention can be applied in connection with other fluids too.
In order to produce an aerodynamically induced force, interaction between the out coming flow and a nearby object must be established. As an applied pressure difference drives the fluid through the conduit, the out coming flow interacts in a perpendicular manner with an object placed further apart from the conduit outlet. When the distance between the conduit outlet and the object facing the outlet is small, in the order of 5 lateral scales of the particular conduit outlet (or more), a jet flow is generated. This jet has a momentum defined by its mass flow rate and velocity. When such a jet impinges on an object, it exerts an aerodynamically induced force on the object. This exerted force depends on the momentum of the jet, as well as on the object specific geometry. A different effect occurs when the distance between the conduit outlet and the object surface is small, in the order of 1 lateral scale of the conduit outlet (or less). In such a case, the fluid is forced to turn sideways. In this cases, the object is also subjected to aerodynamically induced force.
Alternatively, when a fluid is injected parallel to the object surface, it is possible to produce aerodynamically induced force that is substantially parallel to the fluid motion. In such cases, the direction of this essentially xe2x80x9cparallel-to-fluid-motionxe2x80x9d aerodynamically induced force can be altered, according to the local induced pressure that is generated on the interacting surface of the object: It can locally be higher or lower pressure with respect to the average pressure acting on the object.
The design of an injecting system that aims at producing aerodynamically induced force incorporates various aspects, (a) the applied external driving pressure difference, (b) the internal geometric details of the specific conduit of the present invention, (c) the geometry of the conduit inlet and outlet sections, (d) the specific arrangement of the conduits when a plurality of conduits are used, etc. Such aspects and many more are all taken in consideration according to the engineering requirements for a specific application.
The only related prior art references having some relevance to the present invention deal with irrigation emitters only where the fluid passing through it is water which is practically incompressible (as opposed to air or other gases).
U.S. Pat. No. 3,896,999 (Barragan) disclosed an anti-clogging drip irrigation valve, comprising a wide conduit equipped with a plurality of partition means, integrally formed with the conduit wall, forming labyrinth conduits, in order to reduce the water pressure prior to its exit through the labyrinth conduits outlet.
U.S. Pat. No. 4,573,640 (Mehoudar) disclosed an irrigation emitter unit providing a labyrinth conduit similarly to the valve in U.S. Pat. No. 3,896,999. Examples of other devices providing labyrinth conduits for the purpose of providing a pressure drop along the conduit can be found in U.S. Pat. No. 4,060,200 (Mehoudar), U.S. Pat. No. 4,413,787 (Gilead et al.), U.S. Pat. No. 3,870,236 (Sahagun-Barragan), U.S. Pat. No. 4,880,167 (Langa), U.S. Pat. No. 5,620,143 (Delmer et al.), U.S. Pat. No. 4,430,020 (Robbins), U.S. Pat. No. 4,209,133 (Mehoudar), U.S. Pat. No. 4,718,608 (Mehoudar), U.S. Pat. No. 5,207,386 (Mehoudar).
In a labyrinth conduit the aerodynamic resistance is substantially large due to the viscous friction exerted by the walls of the conduit (acting opposite to the direction of the flow), and as the passage becomes tortuous and lengthier (that""s the essential feature of a labyrinth) more wall contact surface is acting on the flow, increasing the viscous friction. In some cases cavities are provided for intercepting contaminants and for freeing the flow passage. None of these patents, which basically deal with two dimensional geometry (the third being either very small or degenerated), mention or make use of a vortical aerodynamic blockage mechanism, that is an essential feature of the present invention.
It is emphasized that while the above mentioned patents deal with the delivery of water through the conduit, the present invention seeks to provide and exploit aerodynamically induced forces, with the fluidxe2x80x94air in most casesxe2x80x94merely serving as the means for generating these forces.
In an article titled xe2x80x9cA FLOW VISUALIZATION STUDY OF THE FLOW IN A 2D ARRAY OF FINSxe2x80x9d (S. Brokman, D Levin, Experiments in Fluids 14, 241-245 (1993)) a study of the flow field in a 2D arrangement of fins was carried out by means of flow visualization in a vertical flow tunnel. The study was related to an earlier studies that examined the fin arrangement as a conceptual heat sink. The above mentioned study went further to examine the complex flow field structure in order to obtain a better understanding of the heat convection process. A model was built of several series of fins, simulating a spatially unlimited multi-cell structure. Two main flow structures were observedxe2x80x94a flow separation from the leading edge of each fin, which due to the influence of neighboring fins, was reattached to the fin, creating a closed separation zone, and a vortex, that filled that closed separation zone.
The Mass Flow Rate (hereafter referred to as MFR) through the conduit (or conduits), the internal pressure drop that is developed within the conduit and the out-coming fluid velocity that define the momentum of the injected fluid as well as the aerodynamically induced force characteristics, are governed by the dynamic laws of fluid flows. Practically speaking, the characteristics of the aerodynamically induced force depend substantially on the fluid characteristics, its dynamic behavior due to the applied driving pressure, on one hand, and on the other hand on the internal geometry of the special conduit of the present invention.
In Israeli Patent Application titled SELF ADAPTIVE SEGMENTED ORIFICE DEVICE AND METHOD (hereafter referred to as SASO), simultaneously filed with the present invention, and incorporated herein by reference, a novel flow control device is disclosed. A typical embodiment of a SASO-device comprises a fluid conduit, having an inlet and outlet, said conduit provided with a plurality of fins mounted on the internal wall of said conduit, said fins arranged in two arrays substantially opposing each other, wherein each of the fins of either one of said fin arrays, excluding the fin nearest to the inlet and the fin nearest to the outlet of said conduit, is positioned opposite one of a plurality of cavities, each cavity defined between two consecutive fins of the other substantially opposite array of fins, and a portion of said internal wall, wherein when a fluid flows through said device a plurality of vortices are formed, each vortex positioned in one of said cavities, said vortices existing at least temporarily during said fluid flow through said device, and a thin core-flow is generated between the two opposite arrays of vortices. The unique advantages of SASO-technology are that it effectively decreases MFR through the SASO-conduit, and most importantly, with respect to fluid injection aimed at generating aerodynamically induced forces, it significantly increases the internal pressure drop within the conduit (hereafter referred to as xcex94P), in comparison with conventional conduits with about the same lateral diameter.
It is the object of the present invention to incorporate SASO-technology in injection systems to produce aerodynamically induced forces, that would improve the performance of such systems which are in common industrial use, and introducing novel systems implementing aerodynamically induced forces.
Furthermore, it is another object of the present invention to provide a wide scope of opportunities to adopt SASO-technology for new applications that could not be obtained with common technologies.
Basically the apparatus and method disclosed herein can operate with any fluid, but air is mainly and essentially the fluid to be considered for a wide scope of applications that take advantage of the special characteristics of the SASO-technology with respect to the aerodynamically induced forces of the present invention.
It is thus provided, in accordance with a preferred embodiment of the present invention, an apparatus for generating a fluid injection induced forces comprising:
a high pressure source; a high pressure reservoir fluidically connected to said high pressure source; an injection surface; at least one conduit of a plurality of conduits;
wherein said conduit has an outlet positioned on said injection surface and an inlet fluidically connected to said high pressure reservoir and is provided with a plurality of fins mounted on the internal wall of said conduit said fins arranged in two arrays substantially opposite each other; wherein each of the fins of either one of said fin arrays excluding the fin nearest to the inlet and the fin nearest to the outlet of said conduit is positioned substantially opposite one of a plurality of cavities each cavity defined between two consecutive fins of one of said arrays of fins and a portion of said conduit internal walls wherein said two opposing fin arrays are arranged asymmetrically; whereby when fluid flows through said conduit a plurality of vortices are formed within said cavities one vortex in a cavity said vortices existing at least temporarily during said flow thus forming an aerodynamic blockage allowing a central core-flow between said vortices and the tips of said fins suppressing the flow in a one-dimensional manner, thus limiting the mass flow rate and maintaining a substantial pressure drop within the conduit, whereby when an object blocks said outlet the flow stops and said vortices dissipate thus said object is effectively forced away by the high pressure aerodynamically induced force whereas when the outlet is not blocked said vortices are formed and aerodynamically blocking the flow through said conduit and whereas said object almost blocks said outlet said vortices substantially collapse and the internal pressure drop through said conduit is gradually changed with respect to the gap between the said injection surface and the facing surface of said object thus said conduit respond as a fluidic return spring when injecting from close distance toward an object; and whereby when said apparatus equipped with at least one of a plurality of said conduits whereas one or a portion of said conduits are not physically blocked by said object the mass flow supply is significantly reduced as said open conduit are aerodynamically blocked by the said vortices.
Furthermore, in accordance with a preferred embodiment of the present invention, said fluid is air.
Furthermore, in accordance with a preferred embodiment of the present invention, said fins are L-shaped where a thin core-flow is suppressed in a two-dimensional manner by said vortices.
Furthermore, in accordance with a preferred embodiment of the present invention, said fins are U-shaped where a thin core-flow is suppressed in a two-dimensional manner by said vortices.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit follows a straight path.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit follows a tortuous path.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit cross-section is substantially rectangular.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit cross-section is substantially polygonal.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit cross-section is substantially circular.
Furthermore, in accordance with a preferred embodiment of the present invention, the downstream distribution of said conduit cross-section area is uniform.
Furthermore, in accordance with a preferred embodiment of the present invention, the downstream distribution of said conduit cross-section area is divergent.
Furthermore, in accordance with a preferred embodiment of the present invention, the downstream distribution of said conduit cross-section area is convergent.
Furthermore, in accordance with a preferred embodiment of the present invention, said fins are substantially perpendicular to said internal wall of the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, said fins are inclined with respect both to the general core-flow direction of motion and to the conduit internal walls.
Furthermore, in accordance with a preferred embodiment of the present invention, the average thickness of each of said fins is smaller in order with comparison to the distance between said fin and the next consecutive fin of the same fin array.
Furthermore, in accordance with a preferred embodiment of the present invention, said fin cross-section is substantially rectangular.
Furthermore, in accordance with a preferred embodiment of the present invention, said fin cross-section is substantially trapezoidal.
Furthermore, in accordance with a preferred embodiment of the present invention, said fin cross-section is substantially concave at least on one side.
Furthermore, in accordance with a preferred embodiment of the present invention, the distance between two consecutive fins is constant along the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the distance between two consecutive fins varies along the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the span of each of said fins is uniform along the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the span of said fins varies along the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the span of said fin is laterally uniform.
Furthermore, in accordance with a preferred embodiment of the present invention, the span of said fin laterally varies.
Furthermore, in accordance with a preferred embodiment of the present invention, the tips of said fins are sharp.
Furthermore, in accordance with a preferred embodiment of the present invention, the tips of said fins are blunt.
Furthermore, in accordance with a preferred embodiment of the present invention, the tips of said fins are curved.
Furthermore, in accordance with a preferred embodiment of the present invention, each of said fins substantially blocks half of the conduit lateral width.
Furthermore, in accordance with a preferred embodiment of the present invention, the two opposite fin arrays do not overlap.
Furthermore, in accordance with a preferred embodiment of the present invention, the two opposite fin arrays overlap.
Furthermore, in accordance with a preferred embodiment of the present invention, the ratio between the fin span and the gap between that fin and a consecutive fin of the same array of fins is in the range of 1:1 to 1:2.
Furthermore, in accordance with a preferred embodiment of the present invention, the said ratio is about 1:1.5.
Furthermore, in accordance with a preferred embodiment of the present invention, the absolute value of the gap between the virtual plane connecting the fin tips of one of said two opposite fin arrays and the virtual plane connecting the fin tips of the second of said two opposite fin arrays is of smaller order than the lateral width of said conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, said absolute value of said gap is not more than 20% of the adjacent lateral width of said conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the size of each of said cavities is slightly smaller than the integrally defined natural scales associated with the vorticity of the vortex formed inside said cavity.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit passive dimension defined as the dimension substantially parallel to said vortices virtual axes and substantially perpendicular to said core-flow motion is in the order of the fins span.
Furthermore, in accordance with a preferred embodiment of the present invention, said passive dimension is substantially larger than the other lateral dimension of the conduit that is substantially perpendicular to both the vortex axis and to the core-flow motion.
Furthermore, in accordance with a preferred embodiment of the present invention, said passive dimension follows a close substantially annular route.
Furthermore, in accordance with a preferred embodiment of the present invention, when Reynolds Number is increased inside said conduit further secondary vortices are formed.
Furthermore, in accordance with a preferred embodiment of the present invention, said core-flow downstream motion is substantially sinusoidal.
Furthermore, in accordance with a preferred embodiment of the present invention, the sinusoidal core-flow strongly interacts with the fins by local impingement of the core flow with the surfaces of the fins facing its motion.
Furthermore, in accordance with a preferred embodiment of the present invention, when Reynolds Number is increased inside said conduit said core-flow breaks down locally and frequently generates unsteady secondary vortices intensively interacting with the core-flow or impinging on the surface of the facing fin.
Furthermore, in accordance with a preferred embodiment of the present invention, said apparatus is used to generate an air cushion.
Furthermore, in accordance with a preferred embodiment of the present invention, at least two air-cushion pads are generated.
Furthermore, in accordance with a preferred embodiment of the present invention, said apparatus is used for air bearing or air cushion.
Furthermore, in accordance with a preferred embodiment of the present invention, said apparatus is conveyed along a predefined pathway without physical contact by floating over an air cushion produced by the apparatus substantially reducing the friction.
Furthermore, in accordance with a preferred embodiment of the present invention, said injection surface defines a predetermined pathway producing an air cushion on which an object is conveyed without physical contact thus substantially reducing friction.
Furthermore, in accordance with a preferred embodiment of the present invention, it is incorporated with another apparatus as claimed in claim 1, said apparati positioned opposite each other, the injection surfaces defining between them a pathway whereby a flat object is conveyed between these surfaces without physical contact with the surfaces.
Furthermore, in accordance with a preferred embodiment of the present invention, a plurality of said conduits are positioned diagonally with respect to said injection surfaces to induce an aerodynamic conveying force in a predetermined direction.
Furthermore, in accordance with a preferred embodiment of the present invention, at least two substantially perpendicular injection surface are used to provide non-contact support or positioning control in a two dimensional manner.
Furthermore, in accordance with a preferred embodiment of the present invention, said injection surface is cylindrically shaped.
Furthermore, in accordance with a preferred embodiment of the present invention, said injection surfaces is the inner cylindrical surface of the stator component of a spindle.
Furthermore, in accordance with a preferred embodiment of the present invention, it is incorporated with another apparatus as claimed in claim 1, wherein injection surfaces of said apparati are cylindrically shaped and are positioned coaxially so that one injection surface is concave and the second injection surface is convex.
Furthermore, in accordance with a preferred embodiment of the present invention, the inner cylindrical injection surface rotates.
Furthermore, in accordance with a preferred embodiment of the present invention, said object is a wafer or a printed circuit board.
Furthermore, in accordance with a preferred embodiment of the present invention, said object is a car carriage or a container or any other storage case.
Furthermore, in accordance with a preferred embodiment of the present invention, said object is a paper sheet or a plastic sheet or a metallic plate including printing plates.
Furthermore, in accordance with a preferred embodiment of the present invention, said air injection induced force is applied in the direction of gravity.
Furthermore, in accordance with a preferred embodiment of the present invention, air injection induced force is applied irrespectful of the gravity.
Furthermore, in accordance with a preferred embodiment of the present invention, air cushion is used for positioning control without contact of said object, said object being stationary.
Furthermore, in accordance with a preferred embodiment of the present invention, air cushion is used for lateral positioning control without contact of said object, said object being conveyed by said apparatus.
Furthermore, in accordance with a preferred embodiment of the present invention, one or a plurality of said conduits that produce fluid injection force act in the gravity direction and are combined with at least one of a plurality of simple vacuum ports that produce fluid suction force that acts against gravity direction whereby when both injection and suction induced force are actuated simultaneously the combined fluid induced force acting on the upper surface of an object hold the object at a stable equilibrium position and balance the object own weight where said object suspended without contact.
Furthermore, in accordance with a preferred embodiment of the present invention, fluid injection by jets is used to hold said object with contact to a surface.
Furthermore, in accordance with a preferred embodiment of the present invention, fluid injection is applied from a distance smaller then the diameter of the injection conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, it is provided an apparatus for generating a fluid injection induced forces comprising:
a high pressure source; a high pressure reservoir fluidically connected to said high pressure source; an injection surface; at least one conduit of a plurality of conduits;
wherein said conduit has an outlet positioned on said injection surface and an inlet fluidically connected to said high pressure reservoir said conduit is provided with a helical fin mounted on the internal wall of said conduit thus a helical cavity is formed defined by said helical fin and said internal wall; wherein when a fluid flows through said conduit a helical vortex is formed within said helical cavity said helical vortex exists at least temporarily during said flow thus forming an aerodynamic blockage allowing a central core-flow between said helical vortex and the tip of said helical fin and suppressing the flow in a two-dimensional manner, thus limiting the mass flow rate and maintaining a substantial pressure drop within the conduit; whereby said core flow flows through a central passage defined by the helical fin internal edge and may locally bypass an obstruction in said central passage by following the helical passage adjacent the helical fin; whereby when an object blocks the outlet of said conduit the flow stops said helical vortex dissipates thus said object is effectively forced away by the high pressure aerodynamically induced force whereas when the outlet is not blocked said helical vortex is formed and aerodynamically partially blocks the flow through said conduit and whereas when said object almost blocks the outlet of said conduit said helical vortex substantially collapses and the internal pressure drop through said conduit is substantially reduced with respect to the internal pressure drop when the vortex existed thus said conduit responds as a fluidic return spring when injecting towards a close object.
Furthermore, in accordance with a preferred embodiment of the present invention, said fluid is air.
Furthermore, in accordance with a preferred embodiment of the present invention, at least one barrier of a plurality of barriers is mounted substantially normally to said helical fin surface thus locally blocking the helical path to prevent the flow from following the helical path and thus said helical vortex locally splits by said barriers to at least two fragments.
Furthermore, in accordance with a preferred embodiment of the present invention, at least one barrier out of two barriers is mounted substantially normally to the fin surface on one of the two ends of said helical fin to act as anchorage for said helical vortex.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit follows a straight path.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit follows a tortuous path.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit cross-section is substantially circular.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit cross-section is substantially rectangular.
Furthermore, in accordance with a preferred embodiment of the present invention, said conduit cross-section is substantially polygonal.
Furthermore, in accordance with a preferred embodiment of the present invention, the downstream distribution of said conduit cross-section area is uniform.
Furthermore, in accordance with a preferred embodiment of the present invention, the downstream distribution of said conduit cross-section area is divergent.
Furthermore, in accordance with a preferred embodiment of the present invention, the downstream distribution of said conduit cross-section area is convergent.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin is substantially perpendicular to said internal wall of the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin is inclined with respect both to the general core-flow direction of motion and the to conduit wall.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin thickness is of smaller order with comparison to the helical fin pitch.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin cross-section is substantially rectangular.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin cross-section is substantially trapezoidal.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin cross-section is substantially concave at least on one side.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin pitch is constant along the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin pitch varies along the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the span of said helical fin is uniform.
Furthermore, in accordance with a preferred embodiment of the present invention, the span of said helical fin varies along the conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the tip of said helical fin is sharp.
Furthermore, in accordance with a preferred embodiment of the present invention, the tip of said helical fin is blunt.
Furthermore, in accordance with a preferred embodiment of the present invention, the tip of said helical fin is curved.
Furthermore, in accordance with a preferred embodiment of the present invention, said helical fin span is substantially half of the said conduit lateral width.
Furthermore, in accordance with a preferred embodiment of the present invention, the ratio between the helical fin span and the helical fin pitch is in the range of 1:1 to 1:2.
Furthermore, in accordance with a preferred embodiment of the present invention, the said ratio is about 1:1.5.
Furthermore, in accordance with a preferred embodiment of the present invention, the central passage defined by the helical fin tip is of smaller order in comparison with the hydraulic diameter of said conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, said gap is not more than 30% of the adjacent lateral width of said conduit.
Furthermore, in accordance with a preferred embodiment of the present invention, the size of said helical cavity is slightly smaller than the integrally defined natural lateral scales associated with the vorticity of the said helical vortex.
Furthermore, in accordance with a preferred embodiment of the present invention, when Reynolds Number is increased inside said conduit further secondary vortices are formed.
Furthermore, in accordance with a preferred embodiment of the present invention, the core-flow strongly interacts with said helical fin by local impingement with the surface of the helical fin facing its motion.
Furthermore, in accordance with a preferred embodiment of the present invention, when Reynolds Number is increased inside said conduit said core-flow breaks down locally and frequently generates unsteady secondary vortices, intensively interacting with the core-flow or impinging on the facing fin.
Furthermore, in accordance with a preferred embodiment of the present invention, said apparatus is used to generate at least one air cushion.
Furthermore, in accordance with a preferred embodiment of the present invention, two air-cushion are generated.
Furthermore, in accordance with a preferred embodiment of the present invention, said apparatus is used in an air bearing or air cushion application.
Furthermore, in accordance with a preferred embodiment of the present invention, said apparatus is moved on a pathway without contact floating over an air cushion produced by the apparatus.
Furthermore, in accordance with a preferred embodiment of the present invention, said injection surface defines a pathway producing an air cushion on which an object is conveyed without contact.
Furthermore, in accordance with a preferred embodiment of the present invention, two opposite flat injection surfaces are provided to define a pathway between said surfaces whereby a flat object is conveyed with no contact.
Furthermore, in accordance with a preferred embodiment of the present invention, said plurality of conduits are positioned diagonally with respect to said injection surfaces to induce an aerodynamic conveying force in a predetermined direction.
Furthermore, in accordance with a preferred embodiment of the present invention, at least two substantially perpendicular injection surface are used to provide non-contact support or positioning control in a two dimensional manner.
Furthermore, in accordance with a preferred embodiment of the present invention, said injection surface is cylindrically shaped.
Furthermore, in accordance with a preferred embodiment of the present invention, said injection surface is the inner cylindrical surface of the stator component of a spindle.
Furthermore, in accordance with a preferred embodiment of the present invention, two opposite injection surfaces are cylindrically shaped where the outer one is concave and the inner one is convex.
Furthermore, in accordance with a preferred embodiment of the present invention, the inner cylindrical injection surfaces rotates.
Furthermore, in accordance with a preferred embodiment of the present invention, said object is a wafer or a printed circuit board.
Furthermore, in accordance with a preferred embodiment of the present invention, said object is a car carriage or a container or any other storage case.
Furthermore, in accordance with a preferred embodiment of the present invention, said object is a paper sheet or a plastic sheet or a metallic plate including printing plates.
Furthermore, in accordance with a preferred embodiment of the present invention, air injection induced force is applied in the direction of gravity.
Furthermore, in accordance with a preferred embodiment of the present invention, air injection induced force is applied irrespectfully of gravity.
Furthermore, in accordance with a preferred embodiment of the present invention, an air cushion is generated for positioning control with no-contact with said object.
Furthermore, in accordance with a preferred embodiment of the present invention, one or a plurality of said conduits that produce fluid injection force acting with gravity direction are combined with at least one of a plurality of simple vacuum ports that produce fluid suction force that acts against gravity direction whereby when both injection and suction induced force are actuated simultaneously the combined fluid induced force acts on the upper surface of an object holds the object at a stable equilibrium position and balances the object own weight said object suspending with no-contact.
Furthermore, in accordance with a preferred embodiment of the present invention, fluid injection by jets is used to hold an object with contact to a surface.
Finally, in accordance with a preferred embodiment of the present fluid injection is applied from a distance smaller then the diameter of the injection conduit.